As is well known, there are various types of earth drilling techniques, including those known as dual tube drilling, wire-line drilling, diamond drilling, conventional drilling, and drilling with augers. Heretofore, drill rigs or apparatus have been especially designed for each different type of drilling and substantial changes of the drill rig were necessary in order to change from one type of drilling to another type of drilling. Further, many conventional drill rigs were specifically adapted for driving one size of drill string. Again, substantial modifications of the apparatus are necessary to adapt the apparatus for a different size of drill string. A still further drawback of conventional drill rigs is that they are not adapted for carrying out all of the functions which are necessary to drive and extract a drill string.
With transportation costs rising at an ever increasing rate and mineral exploration being extended to more remote areas, including mountainous regions, it is becoming more difficult and costly to transport drilling equipment and personel to the drill site. For reasons which are apparent, the helicopter has received much favour as a mode of transportation. However, because of their limited carrying capacity, helicopters are unable to transport heavier conventional drilling rigs to remote locations, particularly those in elevated regions. Thus, there is a need for lighter drilling equipment which can more readily be transported by helicoper or trucks.